Techniques for managing handovers in an unlicensed radio frequency spectrum band

ABSTRACT

Techniques for managing handovers in an unlicensed radio frequency spectrum band may provide that a serving base station may receive one or more base station measurement reports and one or more UE measurement reports. The base station measurement reports may include information associated with one or more devices that may transmit signals using an unlicensed radio frequency spectrum band. The UE measurement reports may include information associated with one or more devices that may generate interfering signals at the UE, which may include interfering signals from one or more devices that are not detected by the serving base station. The serving base station may, in some examples, determine whether to handover the UE to a second base station based at least in part on the base station measurement report and the UE measurement report.

CROSS REFERENCES

The present Application for Patent is a Divisional Application of U.S.patent application Ser. No. 14/956,686 by Damnjanovic, et al., entitled“Techniques for Managing Handovers in an Unlicensed Radio FrequencySpectrum Band” filed Dec. 2, 2015, which claims priority to U.S.Provisional Patent Application No. 62/091,295 by Damnjanovic et al.,entitled “Techniques for Managing Handovers in an Unlicensed RadioFrequency Spectrum Band,” filed Dec. 12, 2014, assigned to the assigneehereof, which is hereby incorporated by reference in its entirety.

BACKGROUND Field of the Disclosure

The present disclosure, for example, relates to wireless communicationsystems, and more particularly to techniques for managing handovers inan unlicensed radio frequency spectrum band.

Description of Related Art

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). Examples of such multiple-access systems include code-divisionmultiple access (CDMA) systems, time-division multiple access (TDMA)systems, frequency-division multiple access (FDMA) systems,single-carrier frequency-division multiple access (SC-FDMA) systems, andorthogonal frequency-division multiple access (OFDMA) systems.

By way of example, a wireless multiple-access communication system mayinclude a number of base stations, each simultaneously supportingcommunication for multiple communication devices, otherwise known asuser equipments (UEs). A base station may communicate with UEs ondownlink channels (e.g., for transmissions from a base station to a UE)and uplink channels (e.g., for transmissions from a UE to a basestation).

Some modes of communication may enable communications between a basestation and a UE over an unlicensed or shared radio frequency spectrumband, or over different radio frequency spectrum bands (e.g., a licensedradio frequency spectrum band or an unlicensed radio frequency spectrumband) of a cellular network. With increasing data traffic in cellularnetworks that use a licensed radio frequency spectrum band, offloadingof at least some data traffic to an unlicensed or unlicensed radiofrequency spectrum band may provide a cellular operator withopportunities for enhanced data transmission capacity. An unlicensedradio frequency spectrum band may also provide service in areas whereaccess to a licensed radio frequency spectrum band is unavailable.

Prior to gaining access to, and communicating over, an unlicensed radiofrequency spectrum band, a base station or UE may perform a listenbefore talk (LBT) procedure to contend for access to the unlicensedradio frequency spectrum band. An LBT procedure may include performing aclear channel assessment (CCA) procedure to determine whether a channelof the unlicensed radio frequency spectrum band is available. When it isdetermined that the channel of the unlicensed radio frequency spectrumband is available, a channel usage beacon signal (CUBS) may betransmitted to reserve the channel.

In some modes of operation, a UE and a serving base station may operateusing an unlicensed radio frequency spectrum band in which the servingbase station may not detect one or more other transmitting device thatmay transmit using the unlicensed radio frequency spectrum band. Forexample, the serving base station may transmit using the unlicensedradio frequency spectrum band in a time division multiplexing mannerwith another base station which may result in the serving base stationtransmitting at the same time as the other device(s) and not detectingthe signals of the other device(s). In other examples, the otherdevice(s) may be outside of an energy detection range of the servingbase station, but close enough to the UE to cause interference. In suchcases, it may be desirable to serve the UE through a different basestation.

SUMMARY

The present disclosure, for example, relates to one or more techniquesfor managing handovers in an unlicensed radio frequency spectrum band.In some examples, a serving base station may receive one or more basestation measurement reports that may include information associated withone or more nodes that may transmit signals using an unlicensed radiofrequency spectrum band. The base station measurement report mayinclude, in some examples, information on one or more nodes that are notdetected by the serving base station, such as due to time divisionmultiplexing of the serving base station, or the nodes being outside ofan energy detection or preamble detection range of the serving basestation, for example. The serving base station also may receive a UEmeasurement report that may include information associated with one ormore nodes that may generate interfering signals at the UE, which mayinclude interfering signals from one or more nodes that are not detectedby the serving base station. The serving base station may, in someexamples, determine whether to handover the UE to a second base station(e.g., a target base station) based at least in part on the base stationmeasurement report and the UE measurement report.

A method of wireless communication at a wireless device is described.The method may include receiving, at a first base station, a basestation measurement report comprising information associated with one ormore first devices that transmits first signals using an unlicensedradio frequency spectrum band, and receiving, at the first base station,a UE measurement report comprising information associated with one ormore second devices that transmits second signals on the unlicensedradio frequency spectrum band.

An apparatus for wireless communication at a wireless device isdescribed. The apparatus may include means for receiving, at a firstbase station, a base station measurement report comprising informationassociated with one or more first devices that transmits first signalsusing an unlicensed radio frequency spectrum band, and means forreceiving, at the first base station, a UE measurement report comprisinginformation associated with one or more second devices that transmitssecond signals on the unlicensed radio frequency spectrum band.

A further apparatus for wireless communication at a wireless device isdescribed. The apparatus may include a processor, memory in electroniccommunication with the processor, and instructions stored in the memory,wherein the instructions are executable by the processor to receive, ata first base station, a base station measurement report comprisinginformation associated with one or more first devices that transmitsfirst signals using an unlicensed radio frequency spectrum band, andreceive, at the first base station, a UE measurement report comprisinginformation associated with one or more second devices that transmitssecond signals on the unlicensed radio frequency spectrum band.

A non-transitory computer-readable medium storing code for wirelesscommunication at a wireless device is described. The code may includeinstructions executable to receive, at a first base station, a basestation measurement report comprising information associated with one ormore first devices that transmits first signals using an unlicensedradio frequency spectrum band, and receive, at the first base station, aUE measurement report comprising information associated with one or moresecond devices that transmits second signals on the unlicensed radiofrequency spectrum band.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, a determination may be madewhether to handover the UE to a second base station based at least inpart on the base station measurement report and the UE measurementreport. In some examples, the one or more first devices comprise one ormore of a non-serving base station or a non-serving wireless local areanetwork (WLAN) access point (AP). Additionally or alternatively, in someexamples the one or more second devices comprise one or more of anon-serving base station or a non-serving WLAN access point (AP).

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the one or more first devicesare within an energy detection range of a base station that provided thebase station measurement report. Additionally or alternatively, in someexamples the one or more second devices are within an energy detectionrange of the UE.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the one or more devices is outof an energy detection range of the first base station. Additionally oralternatively, some examples may include receiving signals at timeintervals that are different from time intervals of transmissions of atleast one of the one or more devices.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the determining whether tohandover the UE to the second base station comprises determining that atleast one of the one or more devices is causing interference at the UEwith signals transmitted from the first base station on the unlicensedradio frequency spectrum band, and determining that the second basestation can transmit signals to the UE with reduced interferencerelative to the first base station. Additionally or alternatively, insome examples the determining whether to handover the UE to the secondbase station further comprises one or more of determining that a signalstrength of transmissions of the second base station at the UE exceeds athreshold value, determining that the second base station is within anenergy detection range of the at least one of the one or more devicesthat is causing interference at the UE, and determining that the secondbase station is within an energy detection range of the first basestation.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, a signal strength of the firstbase station at the UE exceeds a signal strength of the second basestation at the UE. Additionally or alternatively, some examples mayinclude transmitting a handover command to the UE to initiatecommunications between the UE and the second base station.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the base station measurementreport comprises an identification and an energy measurement of at leastone of a non-serving base station or a non-serving WLAN AP. Additionallyor alternatively, in some examples the base station measurement reportfurther comprises preamble detection information for at least one of thenon-serving base station or the non-serving WLAN AP.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the base station measurementreport is received via a backhaul link. Additionally or alternatively,in some examples the UE measurement report comprises an energymeasurement associated with one or more of the second signals receivedat the UE from at least one of the one or more second devices.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the UE measurement reportcomprises a plurality of measurements taken on a plurality offrequencies of the unlicensed radio frequency spectrum band that aredifferent from a frequency of the first base station. Additionally oralternatively, in some examples the UE measurement report comprises aplurality of measurements taken at time intervals having a durationselected to allow the UE to perform measurements of at a least one of abeacon signal for WLAN AP transmissions or a demodulation referencesignal (DRS) signal for other base station transmissions.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the determining whether tohandover the UE to the second base station is based at least in part ona loading metric associated with the second base station. Additionallyor alternatively, in some examples the loading metric comprises channeloccupancy information associated with the second base station.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the second base station isselected based at least in part on the second base station being in anenergy detection range or preamble detect range of an interferingnon-serving base station or an interfering non-serving WLAN AP.

A method of wireless communication at a wireless device is described.The method may include receiving at a UE, from at least one of anon-serving base station or a non-serving WLAN AP, a signal on anunlicensed radio frequency spectrum band, measuring one or moreparameters associated with the signal, transmitting a UE measurementreport to a first base station, the UE measurement report based at leastin part on the one or more measured parameters, and receiving, from thefirst base station, a handover command to initiate communications with asecond base station based at least in part on the UE measurement report.

An apparatus for wireless communication at a wireless device isdescribed. The apparatus may include means for receiving at a UE, fromat least one of a non-serving base station or a non-serving WLAN AP, asignal on an unlicensed radio frequency spectrum band, means formeasuring one or more parameters associated with the signal, means fortransmitting a UE measurement report to a first base station, the UEmeasurement report based at least in part on the one or more measuredparameters, and means for receiving, from the first base station, ahandover command to initiate communications with a second base stationbased at least in part on the UE measurement report.

A further apparatus for wireless communication at a wireless device isdescribed. The apparatus may include a processor, memory in electroniccommunication with the processor, and instructions stored in the memory,wherein the instructions are executable by the processor to receive at aUE, from at least one of a non-serving base station or a non-servingWLAN AP, a signal on an unlicensed radio frequency spectrum band,measure one or more parameters associated with the signal, transmit a UEmeasurement report to a first base station, the UE measurement reportbased at least in part on the one or more measured parameters, andreceive, from the first base station, a handover command to initiatecommunications with a second base station based at least in part on theUE measurement report.

A non-transitory computer-readable medium storing code for wirelesscommunication at a wireless device is described. The code may includeinstructions executable to receive at a UE, from at least one of anon-serving base station or a non-serving WLAN AP, a signal on anunlicensed radio frequency spectrum band, measure one or more parametersassociated with the signal, transmit a UE measurement report to a firstbase station, the UE measurement report based at least in part on theone or more measured parameters, and receive, from the first basestation, a handover command to initiate communications with a secondbase station based at least in part on the UE measurement report.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the UE measurement reportcomprises information associated with a second base station from a samedeployment as the first base station or a third base station from adifferent deployment as the first base station. Additionally oralternatively, in some examples the UE measurement report comprisesinformation associated with one or more WLAN APs that are undetectableby the first base station.

In some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above, the UE measurement reportcomprises a plurality of measurements taken on a plurality offrequencies of the unlicensed radio frequency spectrum band that aredifferent than a frequency of the first base station. Additionally oralternatively, in some examples the UE measurement report comprises aplurality of measurements taken at time intervals having a durationselected to allow the UE to perform measurements of at a least one of abeacon signal for a WLAN AP or a DRS signal for the non-serving basestation.

Some examples of the method, apparatuses, or non-transitorycomputer-readable medium described above may further include performingpreamble detection for the signal, and the UE measurement report furthercomprises preamble detection information associated with the signal.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the following drawings. In theappended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 illustrates an example of a wireless communication system, inaccordance with aspects of the disclosure;

FIG. 2 shows a wireless communication system in which LTE/LTE-A may bedeployed under different scenarios using an unlicensed radio frequencyspectrum band, in accordance with aspects of the present disclosure;

FIG. 3 shows a wireless communication system in which one or more nodesmay generate an interfering signal at a UE, in accordance with aspectsof the present disclosure;

FIG. 4 shows another example of a wireless communication system in whichone or more nodes may generate an interfering signal at a UE, inaccordance with aspects of the present disclosure;

FIG. 5 shows a wireless communication system in which a UE may be handedover to a different base station, in accordance with aspects of thepresent disclosure;

FIG. 6 shows a call flow diagram illustrating operations andcommunications between network devices in a wireless communicationsystem, in accordance with aspects of the present disclosure;

FIG. 7 shows a block diagram of an apparatus configured for use inwireless communication, in accordance with aspects of the presentdisclosure;

FIG. 8 shows a block diagram of a UE for use in wireless communication,in accordance with aspects of the present disclosure;

FIG. 9 shows a block diagram of an apparatus for use in wirelesscommunication, in accordance with aspects of the present disclosure;

FIG. 10 shows a block diagram of a base station (e.g., a base stationforming part or all of an eNB) for use in wireless communication, inaccordance with aspects of the present disclosure;

FIG. 11 shows a block diagram of a multiple input/multiple output (MIMO)communications system including a base station and a UE, in accordancewith aspects of the present disclosure;

FIG. 12 is a flow chart illustrating an example of a method for wirelesscommunication, in accordance with aspects of the present disclosure; and

FIG. 13 is a flow chart illustrating an example of another method forwireless communication, in accordance with aspects of the presentdisclosure.

DETAILED DESCRIPTION

Techniques are described in which an unlicensed radio frequency spectrumband is used for at least a portion of communications over a wirelesscommunication system. In some examples, the unlicensed radio frequencyspectrum band may be used for Long Term Evolution (LTE) communicationsor LTE-Advanced (LTE-A) communications. The unlicensed radio frequencyspectrum band may be used in combination with, or independent from, alicensed radio frequency spectrum band. In some examples, the unlicensedradio frequency spectrum band may be a radio frequency spectrum band forwhich a device may need to contend for access because the radiofrequency spectrum band is available, at least in part, for unlicenseduse, such as Wi-Fi use.

With increasing data traffic in cellular networks that use a licensedradio frequency spectrum band, offloading of at least some data trafficto an unlicensed radio frequency spectrum band may provide a cellularoperator (e.g., an operator of a public land mobile network (PLMN) or acoordinated set of base stations defining a cellular network, such as anLTE/LTE-A network) with opportunities for enhanced data transmissioncapacity. Use of an unlicensed radio frequency spectrum band may alsoprovide service in areas where access to a licensed radio frequencyspectrum band is unavailable. As noted above, before communicating overan unlicensed radio frequency spectrum band, transmitting apparatusesmay perform an LBT procedure to gain access to the medium. Such an LBTprocedure may include performing a CCA procedure (or extended CCAprocedure) to determine whether a channel of the unlicensed radiofrequency spectrum band is available. When it is determined that thechannel of the unlicensed radio frequency spectrum band is available, aCUBS may be transmitted to reserve the channel. When it is determinedthat a channel is not available, a CCA procedure (or extended CCAprocedure) may be performed for the channel again at a later time.

After winning contention for access to an unlicensed radio frequencyspectrum band, a base station may transmit signals to one or more UEs.In some situations, the signals transmitted to the one or more UEs mayexperience interference from one or more other nodes that may transmitusing the unlicensed radio frequency spectrum. For example, the basestation may not detect that a wireless local area network (WLAN) accesspoint (AP) may be transmitting signals using a same portion of theunlicensed radio frequency spectrum band as the base station, which maycause interference with signals received at the UE(s). Such a WLAN APmay not be detected due to, for example, the WLAN AP being outside of anenergy detection range of the base station, or due to the base stationoperating in a time division multiplexed manner with other base stationswhich may prevent the base station from detecting the interfering WLANAP. In some examples, such an interfering node may be another basestation that may be part of a different deployment than the base stationserving the UE, and that the serving base station may not detect forsimilar reasons as mentioned above. Such an interfering WLAN AP or basestation (or other interfering device transmitting using the unlicensedradio frequency spectrum band), may be referred to as a hidden node thatis not detected by a serving base station. According to various aspectsof the disclosure, in the event that a UE experiences interference froma hidden node, the UE may be handed over from a serving base station toa target base station that may reduce such interference and provide formore efficient communications with the UE.

In some examples, a serving base station may receive information relatedto one or more undetected transmitting devices, which may include one ormore hidden nodes, through one or more base station measurement reportsfrom other base stations. In some examples, a UE measurement report maybe used to determine that the UE is experiencing interference from aninterfering node, and one or more base station measurement reports maybe used to determine that another base station may be able to betterserve the UE. Based at least in part on the UE measurement report(s)and/or base station measurement report(s), a serving base station mayinitiate a handover of the UE from the serving base station to a targetbase station.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in other examples.

FIG. 1 illustrates an example of a wireless communication system 100, inaccordance with various aspects of the disclosure. The wirelesscommunication system 100 may include base stations 105, UEs 115, and acore network 130. The core network 130 may provide user authentication,access authorization, tracking, Internet Protocol (IP) connectivity, andother access, routing, or mobility functions. The base stations 105 mayinterface with the core network 130 through backhaul links 132 (e.g.,S1, etc.) and may perform radio configuration and scheduling forcommunication with the UEs 115, or may operate under the control of abase station controller (not shown). In various examples, the basestations 105 may communicate, either directly or indirectly (e.g.,through core network 130), with each other over backhaul links 134(e.g., X2, etc.), which may be wired or wireless communication links.

The base stations 105 may wirelessly communicate with the UEs 115 viaone or more base station antennas. Each of the base station 105 sitesmay provide communication coverage for a respective geographic coveragearea 110. In some examples, a base station 105 may be referred to as abase transceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a Home NodeB, a Home eNodeB, orsome other suitable terminology. The geographic coverage area 110 for abase station 105 may be divided into sectors making up a portion of thecoverage area (not shown). The wireless communication system 100 mayinclude base stations 105 of different types (e.g., macro or small cellbase stations). There may be overlapping geographic coverage areas 110for different technologies.

In some examples, the wireless communication system 100 may include anLTE/LTE-A network. In LTE/LTE-A networks, the term evolved Node B (eNB)may be used to describe the base stations 105, while the term UE may beused to describe the UEs 115. The wireless communication system 100 maybe a Heterogeneous LTE/LTE-A network in which different types of eNBsprovide coverage for various geographical regions. For example, each eNBor base station 105 may provide communication coverage for a macro cell,a small cell, or other types of cell. The term “cell” is a 3GPP termthat can be used to describe a base station, a carrier or componentcarrier associated with a base station, or a coverage area (e.g.,sector, etc.) of a carrier or base station, depending on context.

A macro cell may cover a relatively large geographic area (e.g., severalkilometers in radius) and may allow unrestricted access by UEs withservice subscriptions with the network provider. A small cell may be alower-powered base station, as compared with a macro cell that mayoperate in the same or different (e.g., licensed, shared, etc.) radiofrequency spectrum bands as macro cells. Small cells may include picocells, femto cells, and micro cells according to various examples. Apico cell may cover a relatively smaller geographic area and may allowunrestricted access by UEs with service subscriptions with the networkprovider. A femto cell also may cover a relatively small geographic area(e.g., a home) and may provide restricted access by UEs having anassociation with the femto cell (e.g., UEs in a closed subscriber group(CSG), UEs for users in the home, and the like). An eNB for a macro cellmay be referred to as a macro eNB. An eNB for a small cell may bereferred to as a small cell eNB, a pico eNB, a femto eNB or a home eNB.An eNB may support one or multiple (e.g., two, three, four, and thelike) cells (e.g., component carriers).

The wireless communication system 100 may support synchronous orasynchronous operation. For synchronous operation, the base stations mayhave similar frame timing, and transmissions from different basestations may be approximately aligned in time. For asynchronousoperation, the base stations may have different frame timing, andtransmissions from different base stations may not be aligned in time.The techniques described herein may be used for either synchronous orasynchronous operations.

The communication networks that may accommodate some of the variousdisclosed examples may be packet-based networks that operate accordingto a layered protocol stack. In the user plane, communications at thebearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based.A Radio Link Control (RLC) layer may perform packet segmentation andreassembly to communicate over logical channels. A Medium Access Control(MAC) layer may perform priority handling and multiplexing of logicalchannels into transport channels. The MAC layer may also use Hybrid ARQ(HARD) to provide retransmission at the MAC layer to improve linkefficiency. In the control plane, the Radio Resource Control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and the base stations 105 or corenetwork 130 supporting radio bearers for the user plane data. At thePhysical (PHY) layer, the transport channels may be mapped to Physicalchannels.

The UEs 115 may be dispersed throughout the wireless communicationsystem 100, and each UE 115 may be stationary or mobile. A UE 115 mayalso include or be referred to by those skilled in the art as a mobilestation, a subscriber station, a mobile unit, a subscriber unit, awireless unit, a remote unit, a mobile device, a wireless device, awireless communications device, a remote device, a mobile subscriberstation, an access terminal, a mobile terminal, a wireless terminal, aremote terminal, a handset, a user agent, a mobile client, a client, orsome other suitable terminology. A UE 115 may be a cellular phone, apersonal digital assistant (PDA), a wireless modem, a wirelesscommunication device, a handheld device, a tablet computer, a laptopcomputer, a cordless phone, a wireless local loop (WLL) station, or thelike. A UE may be able to communicate with various types of basestations and network equipment, including macro eNBs, small cell eNBs,relay base stations, WLAN APs, and the like.

The communication links 125 shown in wireless communication system 100may include downlink (DL) transmissions, from a base station 105 to a UE115, or uplink (UL) transmissions, from a UE 115 to a base station 105.The downlink transmissions may also be called forward linktransmissions, while the uplink transmissions may also be called reverselink transmissions. In some examples, UL transmissions may includetransmissions of uplink control information, which uplink controlinformation may be transmitted over an uplink control channel (e.g., aphysical uplink control channel (PUCCH) or enhanced PUCCH (ePUCCH)). Theuplink control information may include, for example, acknowledgements ornon-acknowledgements of downlink transmissions, or channel stateinformation. UL transmissions may also include transmissions of data,which data may be transmitted over a physical uplink shared channel(PUSCH) or enhanced PUSCH (ePUSCH). UL transmissions may also includethe transmission of a sounding reference signal (SRS) or enhanced SRS(eSRS), a physical random access channel (PRACH) or enhanced PRACH(ePRACH) (e.g., in the standalone mode described with reference to FIG.2), or a scheduling request (SR) or enhanced SR (eSR) (e.g., in thestandalone mode described with reference to FIG. 2). References in thisdisclosure to a PUCCH, a PUSCH, a PRACH, an SRS, or an SR are presumedto inherently include references to a respective ePUCCH, ePUSCH, ePRACH,eSRS, or eSR.

In some examples, each communication link 125 may include one or morecarriers, where each carrier may be a signal made up of multiplesub-carriers (e.g., waveform signals of different frequencies) modulatedaccording to the various radio technologies described above. Eachmodulated signal may be sent on a different sub-carrier and may carrycontrol information (e.g., reference signals, control channels, etc.),overhead information, user data, etc. The communication links 125 maytransmit bidirectional communications using a frequency domain duplexing(FDD) operation (e.g., using paired spectrum resources) or a time domainduplexing (TDD) operation (e.g., using unpaired spectrum resources).Frame structures for FDD operation (e.g., frame structure type 1) andTDD operation (e.g., frame structure type 2) may be defined.

In some examples of the wireless communication system 100, base stations105 or UEs 115 may include multiple antennas for employing antennadiversity schemes to improve communication quality and reliabilitybetween base stations 105 and UEs 115. Additionally or alternatively,base stations 105 or UEs 115 may employ multiple-input, multiple-output(MIMO) techniques that may take advantage of multi-path environments totransmit multiple spatial layers carrying the same or different codeddata.

The wireless communication system 100 may support operation on multiplecells or carriers, a feature which may be referred to as carrieraggregation (CA) or dual-connectivity operation. A carrier may also bereferred to as a component carrier (CC), a layer, a channel, etc. Theterms “carrier,” “component carrier,” “cell,” and “channel” may be usedinterchangeably herein. A UE 115 may be configured with multipledownlink CCs and one or more uplink CCs for carrier aggregation. Carrieraggregation may be used with both FDD and TDD component carriers.

In some examples, the wireless communication system 100 may supportoperation over a licensed radio frequency spectrum band (e.g., a radiofrequency spectrum band for which transmitting apparatuses may notcontend for access because the radio frequency spectrum band is licensedto one or more users for some uses, such as a licensed radio frequencyspectrum band usable for LTE/LTE-A communications) or an unlicensedradio frequency spectrum band (e.g., a radio frequency spectrum band forwhich transmitting apparatuses may need to contend for access becausethe radio frequency spectrum band is available for shared use bymultiple users, such as Wi-Fi use). Upon winning a contention for accessto the unlicensed radio frequency spectrum band, a transmittingapparatus (e.g., a base station 105 or UE 115) may transmit one or moreCUBS over the unlicensed radio frequency spectrum band. The CUBS mayreserve the unlicensed radio frequency spectrum by providing adetectable energy on the unlicensed radio frequency spectrum band. TheCUBS may also serve to identify the transmitting apparatus or serve tosynchronize the transmitting apparatus and a receiving apparatus.

FIG. 2 shows a wireless communication system 200 in which LTE/LTE-A maybe deployed under different scenarios using an unlicensed radiofrequency spectrum band, in accordance with various aspects of thepresent disclosure. More specifically, FIG. 2 illustrates examples of asupplemental downlink mode (also referred to as an unlicensed downlinkmode), a carrier aggregation mode, and a standalone mode in whichLTE/LTE-A may be deployed using an unlicensed radio frequency spectrumband. The wireless communication system 200 may be an example ofportions of the wireless communication system 100 described withreference to FIG. 1. Moreover, a first base station 205 and a secondbase station 205-a may be examples of aspects of one or more of the basestations 105 described with reference to FIG. 1, while a first UE 215, asecond UE 215-a, a third UE 215-b, and a fourth UE 215-c may be examplesof aspects of one or more of the UEs 115 described with reference toFIG. 1.

In the example of a supplemental downlink mode in the wirelesscommunication system 200, the first base station 205 may transmit OFDMAwaveforms to the first UE 215 using a downlink channel 220. The downlinkchannel 220 may be associated with a frequency F1 in an unlicensed radiofrequency spectrum band. The first base station 205 may transmit OFDMAwaveforms to the first UE 215 using a first bidirectional link 225 andmay receive SC-FDMA waveforms from the first UE 215 using the firstbidirectional link 225. The first bidirectional link 225 may beassociated with a frequency F4 in a licensed radio frequency spectrumband. The downlink channel 220 in the unlicensed radio frequencyspectrum band and the first bidirectional link 225 in the licensed radiofrequency spectrum band may operate contemporaneously. The downlinkchannel 220 may provide a downlink capacity offload for the first basestation 205. In some examples, the downlink channel 220 may be used forunicast services (e.g., addressed to one UE) or for multicast services(e.g., addressed to several UEs). This scenario may occur with anyservice provider (e.g., a mobile network operator (MNO)) that uses alicensed radio frequency spectrum and needs to relieve some of thetraffic or signaling congestion.

In one example of a carrier aggregation mode in the wirelesscommunication system 200, the first base station 205 may transmit OFDMAwaveforms to the second UE 215-a using a second bidirectional link 230and may receive OFDMA waveforms, SC-FDMA waveforms, or resource blockinterleaved FDMA waveforms from the second UE 215-a using the secondbidirectional link 230. The second bidirectional link 230 may beassociated with the frequency F1 in the unlicensed radio frequencyspectrum band. The first base station 205 may also transmit OFDMAwaveforms to the second UE 215-a using a third bidirectional link 235and may receive SC-FDMA waveforms from the second UE 215-a using thethird bidirectional link 235. The third bidirectional link 235 may beassociated with a frequency F2 in a licensed radio frequency spectrumband. The second bidirectional link 230 may provide a downlink anduplink capacity offload for the first base station 205. Like thesupplemental downlink described above, this scenario may occur with anyservice provider (e.g., MNO) that uses a licensed radio frequencyspectrum and needs to relieve some of the traffic or signalingcongestion.

In another example of a carrier aggregation mode in the wirelesscommunication system 200, the first base station 205 may transmit OFDMAwaveforms to the third UE 215-b using a fourth bidirectional link 240and may receive OFDMA waveforms, SC-FDMA waveforms, or resource blockinterleaved waveforms from the third UE 215-b using the fourthbidirectional link 240. The fourth bidirectional link 240 may beassociated with a frequency F3 in the unlicensed radio frequencyspectrum band. The first base station 205 may also transmit OFDMAwaveforms to the third UE 215-b using a fifth bidirectional link 245 andmay receive SC-FDMA waveforms from the third UE 215-b using the fifthbidirectional link 245. The fifth bidirectional link 245 may beassociated with the frequency F2 in the licensed radio frequencyspectrum band. The fourth bidirectional link 240 may provide a downlinkand uplink capacity offload for the first base station 205. This exampleand those provided above are presented for illustrative purposes andthere may be other similar modes of operation or deployment scenariosthat combine LTE/LTE-A in a licensed radio frequency spectrum band anduse an unlicensed radio frequency spectrum band for capacity offload.

As described above, one type of service provider that may benefit fromthe capacity offload offered by using LTE/LTE-A in an unlicensed radiofrequency spectrum band is a traditional MNO having access rights to anLTE/LTE-A licensed radio frequency spectrum band. For these serviceproviders, an operational example may include a bootstrapped mode (e.g.,supplemental downlink, carrier aggregation) that uses the LTE/LTE-Aprimary component carrier (PCC) on the licensed radio frequency spectrumband and at least one secondary component carrier (SCC) on theunlicensed radio frequency spectrum band.

In the carrier aggregation mode, data and control may, for example, becommunicated in the licensed radio frequency spectrum band (e.g., viafirst bidirectional link 225, third bidirectional link 235, and fifthbidirectional link 245) while data may, for example, be communicated inthe unlicensed radio frequency spectrum band (e.g., via secondbidirectional link 230 and fourth bidirectional link 240). The carrieraggregation mechanisms supported when using an unlicensed radiofrequency spectrum band may fall under a hybrid frequency divisionduplexing-time division duplexing (FDD-TDD) carrier aggregation or aTDD-TDD carrier aggregation with different symmetry across componentcarriers.

In one example of a standalone mode in the wireless communication system200, the second base station 205-a may transmit OFDMA waveforms to thefourth UE 215-c using a bidirectional link 250 and may receive OFDMAwaveforms, SC-FDMA waveforms, or resource block interleaved FDMAwaveforms from the fourth UE 215-c using the bidirectional link 250. Thebidirectional link 250 may be associated with the frequency F3 in theunlicensed radio frequency spectrum band. The standalone mode may beused in non-traditional wireless access scenarios, such as in-stadiumaccess (e.g., unicast, multicast). An example of a type of serviceprovider for this mode of operation may be a stadium owner, cablecompany, event host, hotel, enterprise, or large corporation that doesnot have access to a licensed radio frequency spectrum band.

FIG. 3 shows a wireless communication system 300 in which one or morenodes may generate an interfering signal at a UE, in accordance withvarious aspects of the present disclosure. The wireless communicationsystem 300 may be an example of portions of the wireless communicationsystem 100 or 200 described with reference to FIG. 1 or 2. Moreover,base stations 305 of FIG. 3 may be examples of aspects of one or more ofthe base stations 105, or 205 described with reference to FIG. 1 or 2,while UEs 315 of FIG. 3 may be examples of aspects of one or more of theUEs 115 or 215 described with reference to FIG. 1 or 2.

As illustrated in the example of FIG. 3, wireless communication system300 may include a first base station 305-a that may act as a servingbase station to a first UE 315-a, and may communicate with the first UE315-a through a communication link 335. As discussed above, in somesituations first UE 315-a may experience interference in the receptionand/or transmission of signals on communication link 335 from one ormore interfering signals 345-a that may be received from a WLAN AP 310.For example, the WLAN AP 310 may be within an energy detection range orpreamble detection (PD) range of the first UE 315-a. WLAN AP 310 may bein Wi-Fi communications, for example, with a second UE 315-b viacommunication link 340. The first base station 305-a may not detecttransmissions from WLAN AP 310 because, for example, the WLAN AP 310 maynot be within an energy detection range or PD range 350-a of the firstbase station 305-a. The WLAN AP 310 may be within an energy detectionrange or PD range 350-b of the second base station 305-b, for example,the second base station 305-b may detect transmission via communicationlink 340 between the WLAN AP 310 and the second UE 315-b. In someexamples the second base station 305-b may receive signals 345-b fromthe WLAN AP 310.

For example, the second base station 305-b may detect one or moretransmissions of WLAN AP 310. The second base station 305-b maydetermine information related to the WLAN AP 310 based at least in parton the detected transmissions of WLAN AP 310. The second base station305-b may generate a base station measurement report of one or morenodes (e.g., WLAN AP 310 and/or third base station 305-c) within anenergy detection range or PD range 350-b of the second base station305-b. The second base station 305-b may include information related tothe WLAN AP 310 in a base station measurement report that may beprovided to the first base station 305-a via a backhaul communicationlink 334 (e.g., an X2 interface such as X2 interface 134 of FIG. 1). Thebase station measurement report of the second base station 305-b mayalso include information related to a third base station 305-c, whichmay transmit signals using the unlicensed radio frequency spectrum bandaccording to a different deployment (e.g., deployed by a differentpublic land mobile network (PLMN) operator) than a deployment of thefirst base station 305-a or second base station 305-b.

Additionally, according to various examples, the first UE 315-a maygenerate and transmit a UE measurement report that may indicate that theinterfering signal 345-a from the WLAN AP 310 is causing interference atthe first UE 315-a. The UE measurement report may be transmitted to thefirst base station 305-a via communication link 335. The UE measurementreport may include, for example, measurements of signals received frombase station(s) from the same deployment and different deployments fromthe first base station 305-a, and measurement information for signalsdetected from WLAN APs such as WLAN AP 310. Such measurements may beperformed by the first UE 315-a on carrier frequencies different from aserving carrier frequency of the first base station 305-a, as well asmeasurements from the serving carrier frequency. In some examples, ameasurement gap between sampling of the different frequencies for suchUE measurements may be long enough to allow the first UE 315-a toperform measurements of at least beacon signals for Wi-Fi transmissionsand demodulation reference signals (DRS) for LTE base stations. In someexamples, the measurement gap may be set to allow the first UE 315-a todetermine a preamble for Wi-Fi transmissions and also a preamble/CUBSfor signals from other base stations.

In some examples, the first base station 305-a may use the UEmeasurement report and the base station measurement report to determinethat the first UE 315-a may be handed over to the second base station305-b, as will be discussed in more detail below. While FIG. 3illustrates a WLAN AP 310 generating an interfering signal 345-a, suchinterference may be generated from other nodes in the wirelesscommunications system 300, such as the third base station 305-c, asdescribed below with respect to FIG. 4.

FIG. 4 shows another example of a wireless communication system 400 inwhich one or more nodes may generate an interfering signal at a UE, inaccordance with various aspects of the present disclosure. The wirelesscommunication system 400 may be an example of portions of the wirelesscommunication system 100, 200, or 300 described with reference to FIG.1, 2 or 3. Moreover, base stations 405 of FIG. 4 may be examples ofaspects of one or more of the base stations 105, 205, or 305 describedwith reference to FIG. 1, 2, or 3 while UEs 415 of FIG. 4 may beexamples of aspects of one or more of the UEs 115, 215, or 315 describedwith reference to FIG. 1, 2, or 3.

As illustrated in the example of FIG. 4, wireless communication system400 may include a first base station 405-a that may act as a servingbase station to a first UE 415-a, and may communicate with the first UE415-a through a communication link 435. As discussed above, in somesituations first UE 415-a may experience interference in the receptionand/or transmission of signals on communication link 435 from one ormore interfering signals 445-a that may be received from third basestation 405-c. For example, the third base station 405-c may be withinan energy detection range or preamble detection (PD) range of the firstUE 415-a. The third base station 405-c may transmit signals, in someexamples, using the unlicensed radio frequency spectrum band to a secondUE 415-b on communication link 440 according to a different deploymentthan a deployment of the first base station 405-a or second base station405-b (e.g., deployed by a different public land mobile network (PLMN)operator).

The first base station 405-a may not detect signals from the third basestation 405-c because, for example, the third base station 405-c may notbe within an energy detection range or PD range 450-a of the first basestation 405-a. In some examples, the first base station 405-a and/orthird base station 405-c may use time division multiplexing (TDM) foraccess to the unlicensed radio frequency spectrum band, such that thefirst base station 405-a receives signals at time intervals that aredifferent from time intervals of transmissions of third base station405-c. The third base station 405-c may be within an energy detectionrange or PD range 450-b of the second base station 405-b, or the secondbase station 405-b may have a TDM configuration that allows forreception of signals 445-b from the third base station 405-c.

For example, the second base station 405-b may detect one or moretransmissions of third base station 405-c. The second base station 405-bmay determine information related to the third base station 405-c basedat least in part on the detected transmissions of third base station405-c. The second base station 405-b may generate a base stationmeasurement report of one or more nodes (e.g., WLAN AP 410 and/or thirdbase station 405-c) within an energy detection range or preambledetection (PD) range 450-b of the second base station 405-b. The secondbase station 405-b may include information related to the third basestation 405-c in a base station measurement report that may be providedto the first base station 405-a via a backhaul communication link 434(e.g., an X2 interface such as X2 interface 134 of FIG. 1), similarly asdiscussed above with respect to FIG. 3. The base station measurementreport of the second base station 405-b may also include informationrelated to WLAN AP 410, which may transmit Wi-Fi signals using theunlicensed radio frequency spectrum band, for example. Additionally,according to various examples, the first UE 415-a may generate andtransmit a UE measurement report that may indicate that the interferingsignal 445-a from the third base station 405-c is causing interferenceat the first UE 415-a. The UE measurement report may be transmitted tothe first base station 405-a via communication link 435, and may includeinformation determined at measurement gaps such as discussed above withrespect to FIG. 3. In some examples, the first base station 405-a mayuse the UE measurement report and the base station measurement report todetermine that the first UE 415-a may be handed over to the second basestation 405-b, as will be discussed in more detail below.

As discussed above, it may be determined that a UE is to be handed overto a different base station in the event that it is determined that theUE is experiencing interference from one or more nodes operating in awireless communications system. FIG. 5 shows a wireless communicationsystem 500 in which a UE may be handed over to a different base station,in accordance with various aspects of the present disclosure. Thewireless communication system 500 may be an example of portions of thewireless communication system 100, 200, 300, or 400 described withreference to FIG. 1, 2, 3, or 4. Moreover, base stations 505 of FIG. 5may be examples of aspects of one or more of the base stations 105, 205,305, or 405 described with reference to FIG. 1, 2, 3, or 4, while UE 515of FIG. 5 may be an example of aspects of one or more of the UEs 115,215, 315, or 415 described with reference to FIG. 1, 2, 3, or 4.

In the example of FIG. 5, the first base station 505-a may receive oneor more base station measurement reports from second base station 505-b(and/or other base stations not shown), and may receive one or more UEmeasurement reports from a UE 515 (and/or other UEs not shown). The basestation measurement report(s) may be provided via a backhaul link 534(such as X2 interface 134 of FIG. 1). The UE measurement report(s) maybe provided via communications link 525-a. The base station measurementreport(s), and the UE measurement report(s) may include informationrelated to, for example, a third base station 505-c and a WLAN AP 510,which may or may not be detectable by the first base station 505-a forreasons similarly as discussed above. In the event that the first basestation 505-a determines that the UE 515 is experiencing interferencefrom a hidden node (e.g., interference from signals transmitted by anon-serving third base station 505-c or a non-serving WLAN AP 510, wherethe non-serving third base station 505-c or a non-serving WLAN AP 510may not be detectable by the first base station 505-a), the first basestation 505-a may determine that the UE 515 is to be handed over to atarget base station, such as second base station 505-b.

In some examples, the determination of the target base station may bemade, at least in part, based on the base station measurement report(s)and the UE measurement report(s). For example, the target base stationmay be selected as a base station that is within an energy detectionrange or preamble detection range (e.g., energy detection range orpreamble detection range 550-b of second base station 505-b) of theinterfering node (e.g., third base station 505-c or WLAN AP 510). Insome examples, the target base station (e.g., second base station 505-b)may be selected as a base station that is within an energy detectionrange or preamble detection range 550-a of the first base station 505-a.Additionally, in some examples, the target base station may be selectedbased at least in part on whether a signal strength of the target basestation at the UE 515 exceeds a signal strength threshold, and thusprovides a signal that is sufficiently strong to provide effectivewireless communications.

In some examples, the signal strength of the target base station at theUE 515 may be less than the signal strength of the first base station505-a. In some examples, the UE 515 may provide preamble detection ofthe interfering signal to identify interfering node, although in otherexamples, DRS or beacon signal measurements may be sufficient for thefirst base station 505-a to identify the interfering node. In furtherexamples, the second base station 505-b (and/or other base stations notshown) may provide loading information to the first base station 505-a,which may be taken into account when making the handover determination.Such loading information may include, for example, channel occupancy ofthe second base station 505-b.

FIG. 6 shows a call flow diagram 600 illustrating operations andcommunications between network devices in a wireless communicationsystem, in accordance with various aspects of the present disclosure.The call flow diagram 600 may illustrate aspects of the wirelesscommunications systems 100, 200, 300, 400, or 500 described withreference to FIG. 1, 2, 3, 4, or 5, respectively. The call flow diagram600 includes a UE 615, a first base station 605-a, and a second basestation 605-b. The UE 615 may be an example of one or more of the UEs115, 215, 315, 415, or 515 described above with respect to FIG. 1, 2, 3,4, or 5. The base stations 605 may be examples of one or more of thebase stations 105, 205, 305, 405, or 505 described above with respect toFIG. 1, 2, 3, 4, or 5. In some examples, the first base station 605-amay be a serving base station of the UE 615, and the second base station605-b may be a target base station of a handover procedure. The callflow diagram 600 illustrates aspects of implementing handover operationsfor based on detection of one or more interfering nodes that maytransmit interfering communications to UE 615. In some examples, asystem device, such as one of the UE 615 or base stations 605 mayexecute one or more sets of codes to control the functional elements ofthe device to perform some or all of the functions described below.

At block 620, the first base station 605-a may perform base stationmeasurements and may generate a base station measurement report, whichmay include a preamble detection (PD) list of neighboring base stationsand WLAN APs with a PD range of the first base station 605-a. At block625, the second base station 605-b may perform base station measurementsand may generate a base station measurement report, which may include aPD list of neighboring base stations and WLAN APs with a PD range of thesecond base station 605-b. The first base station 605-a and second basestation 605-b may exchange measurement reports, as indicated at 630,such as via a backhaul link. In some examples, the first base station605-a and second base station 605-b optionally may exchange loadinformation, as indicated at 635.

At block 640, the UE 615 may measure parameters associated with one ormore received signals and generate a UE measurement report. The UEmeasurement report may be transmitted to the first base station 605-a,as indicated at 645. At block 650, the first base station 605-a may makea handover decision based on the measurement reports, PD lists, or loadinformation (or combination thereof). In the event that the first basestation 605-adetermines to handover the UE 615 to the second basestation 605-b, a handover command 655 may be transmitted to the UE 615.An access procedure 660 may then be initiated between the first basestation 605-a and the second base station 605-b to perform the handoveraccording to established handover techniques.

FIG. 7 shows a block diagram 700 of an apparatus 705 configured for usein wireless communication, in accordance with various aspects of thepresent disclosure. The apparatus 705 may be an example of aspects ofone or more of the UEs 115, 215, 315, 415, 515, or 615 described withreference to FIG. 1, 2, 3, 4, 5, or 6. The apparatus 705 may also be orinclude a processor. The apparatus 705 may include a receiver 710, ameasurement report component 715, and a transmitter 720. At least one ofthese components may be in communication with each other.

The components of the apparatus 705 may, individually or collectively,be implemented using one or more application-specific integratedcircuits (ASICs) adapted to perform some or all of the applicablefunctions in hardware. Alternatively, the functions may be performed byone or more other processing units (or cores), on one or more integratedcircuits. In other examples, other types of integrated circuits may beused (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays(FPGAs), and other Semi-Custom ICs), which may be programmed in anymanner known in the art. The functions of each component may also beimplemented, in whole or in part, with instructions embodied in amemory, formatted to be executed by one or more general orapplication-specific processors.

In some examples, the receiver 710 may include at least one radiofrequency (RF) receiver, such as at least one RF receiver operable toreceive transmissions over a licensed radio frequency spectrum band(e.g., a radio frequency spectrum band for which transmittingapparatuses may not contend for access because the radio frequencyspectrum band is licensed to one or more users for some uses, such as alicensed radio frequency spectrum band usable for LTE/LTE-Acommunications) or an unlicensed radio frequency spectrum band (e.g., aradio frequency spectrum band for which transmitting apparatuses mayneed to contend for access because the radio frequency spectrum band isavailable for unlicensed use, such as Wi-Fi use). In some examples, thelicensed radio frequency spectrum band or the unlicensed radio frequencyspectrum band may be used for LTE/LTE-A communications, as described,for example, with reference to FIG. 1, 2, 3, 4, 5, or 6. The receiver710 may be used to receive various types of data or control signals(i.e., transmissions) over one or more communication links of a wirelesscommunication system, such as one or more communication links of thewireless communication system 100, 200, 300, 400, or 500 described withreference to FIG. 1, 2, 3, 4, or 5. The communication links may beestablished over the licensed radio frequency spectrum band or theunlicensed radio frequency spectrum band.

In some examples, the transmitter 720 may include at least one RFtransmitter, such as at least one RF transmitter operable to transmitover the licensed radio frequency spectrum band or the unlicensed radiofrequency spectrum band. The transmitter 720 may be used to transmitvarious types of data or control signals (i.e., transmissions) over oneor more communication links of a wireless communication system, such asone or more communication links of the wireless communication system100, 200, 300, 400, or 500 described with reference to FIG. 1, 2, 3, 4,or 5. The communication links may be established over the licensed radiofrequency spectrum band or the unlicensed radio frequency spectrum band.In some examples, the transmitter 720 may be collocated with thereceiver 710 in a transceiver.

In some examples, the measurement report component 715 may be used tomeasure one or more parameters of signals received at the apparatus 705via receiver 710 and generate a measurement report for transmission bythe transmitter 720. The one or more parameters measured by themeasurement report component 715 may include, for example, one or moreof a signal strength of transmissions of one or more devices that maytransmit signals using the licensed radio frequency spectrum band orunlicensed radio frequency spectrum band, an identification of the oneor more devices, measurements taken on a plurality of frequencies of theunlicensed radio frequency spectrum band or licensed radio frequencyspectrum band that are different from a frequency of a serving basestation, or a plurality of measurements taken at time intervals having aduration selected to allow the apparatus 705 to perform measurements ofat a least one of a beacon signal for a WLAN AP or a demodulationreference signal (DRS) signal for base station transmissions. Themeasurement report component 715 also may determine that one or moresignals received at the apparatus 705 is causing interference with asignal from a serving base station, and may include an identification ofthe interfering signal(s) in a measurement report, such as preambledetection information of CUBS information associated with theinterfering signal(s), for example.

In some examples, the measurement report component 715 may include asignal identification component 725, a signal parameter measurementcomponent 730, or a measurement report generation component 735. Thesignal identification component 725 may perform, for example, preambleidentification or CUBS identification for one or more signals receivedusing the unlicensed radio frequency spectrum band, in a mannersimilarly as described above with respect to FIG. 1, 2, 3, 4, or 5. Insome examples, the signal parameter measurement component 730 mayperform various measurements on received signals, such as, for example,signal strength of the received signals or timing of receipt of thesignals, in a manner similarly as described above with respect to FIG.1, 2, 3, 4, or 5. In some examples, the measurement report generationcomponent 735 may generate one or more measurement reports that may beprovided to, for example, a serving base station, in a manner similarlyas described above with respect to FIG. 1, 2, 3, 4, or 5.

FIG. 8 shows a block diagram 800 of a UE 815 for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. The UE 815 may have various configurations and may beincluded or be part of a personal computer (e.g., a laptop computer, anetbook computer, a tablet computer, etc.), a cellular telephone, a PDA,a digital video recorder (DVR), an internet appliance, a gaming console,an e-reader, etc. The UE 815 may, in some examples, have an internalpower supply (not shown), such as a small battery, to facilitate mobileoperation. In some examples, the UE 815 may be an example of aspects ofone or more of the UE 115, 215, 315, 415, 515, or 615 described withreference to FIG. 1, 2, 3, 4, 5, or 6, or aspects of the apparatus 705described with reference to FIG. 7. The UE 815 may be configured toimplement at least some of the UE or apparatus features and functionsdescribed with reference to FIG. 1, 2, 3, 4, 5, 6, or 7.

The UE 815 may include a UE processor 805, a UE memory 810, at least onetransceiver (represented by UE transceiver 835), at least one antenna(represented by UE antennas 840), a measurement report component 825, ora handover component 830. At least one of these components may be incommunication with each other, directly or indirectly, over one or morebuses 845.

The UE memory 810 may include random access memory (RAM) or read-onlymemory (ROM). The UE memory 810 may store computer-readable,computer-executable code 820 containing instructions that are configuredto, when executed, cause the UE processor 805 to perform variousfunctions described herein related to wireless communication, includingthe performance of parameter measurement, UE measurement reportgeneration, and handover operations. Alternatively, the code 820 may notbe directly executable by the UE processor 805 but be configured tocause the UE 815 (e.g., when compiled and executed) to perform variousaspects of the functions described herein.

The UE processor 805 may include an intelligent hardware device, e.g., acentral processing unit (CPU), a microcontroller, an ASIC, etc. The UEprocessor 805 may process information received through the UEtransceiver 835 or information to be sent to the UE transceiver 835 fortransmission through the UE antennas 840. The UE processor 805 mayhandle, alone or in connection with the measurement report component 825and handover component 830, various aspects of communicating over alicensed radio frequency spectrum band or an unlicensed radio frequencyspectrum band, including handovers to different base stations based onone or more interfering signals received at the UE 815.

The UE transceiver 835 may include a modem configured to modulatepackets and provide the modulated packets to the UE antennas 840 fortransmission, and to demodulate packets received from the UE antennas840. The UE transceiver 835 may, in some examples, be implemented as oneor more transmitters and one or more separate receivers. The UEtransceiver 835 may support communications in the licensed radiofrequency spectrum band or the unlicensed radio frequency spectrum band.The UE transceiver 835 may be configured to communicatebi-directionally, via the UE antennas 840, with one or more of the basestations 105, 205, 305, 405, 505 or 605 described with reference to FIG.1, 2, 3, 4, 5, or 6. While the UE 815 may include a single UE antenna,there may be examples in which the UE 815 may include multiple UEantennas 840.

The handover component 830 may be used, for example, to managetransitions of the UE 815 between a serving base station and a targetbase station, and may be in communication with other components of theUE 815, directly or indirectly, over the one or more buses 845. Thehandover component 830, or portions of it, may include a processor, orsome or all of the functions of the handover component 830 may beperformed by the UE processor 805 or in connection with the UE processor805.

The measurement report component 825 may be configured to perform orcontrol some or all of the UE or apparatus features or functionsdescribed with reference to FIG. 1, 2, 3, 4, 5, 6, or 7 related towireless communication over a licensed radio frequency spectrum band oran unlicensed radio frequency spectrum band. For example, themeasurement report component 825 may be configured to perform parametermeasurements and generate UE measurement reports for transmission to aserving base station for use in determining if the UE 815 should behanded over to a different base station. The measurement reportcomponent 825, or portions of it, may include a processor, or some orall of the functions of the measurement report component 825 may beperformed by the UE processor 805 or in connection with the UE processor805. In some examples, the measurement report component 825 may be anexample of the measurement report component 715 described with referenceto FIG. 7.

FIG. 9 shows a block diagram 900 of an apparatus 905 for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. In some examples, the apparatus 905 may be an example ofaspects of one or more of the base stations 105, 205, 305, 405, 505, or605 described with reference to FIG. 1, 2, 3, 4, 5, or 6. In someexamples, the apparatus 905 may be part or include an LTE/LTE-A eNBand/or an LTE/LTE-A base station. The apparatus 905 may also be aprocessor. The apparatus 905 may include a receiver 910, a handovermanagement component 915, and a transmitter 920. At least one of thesecomponents may be in communication with each other.

The components of the apparatus 905 may, individually or collectively,be implemented using one or more ASICs adapted to perform some or all ofthe applicable functions in hardware. Alternatively, the functions maybe performed by one or more other processing units (or cores), on one ormore integrated circuits. In other examples, other types of integratedcircuits may be used (e.g., Structured/Platform ASICs, FPGAs, and otherSemi-Custom ICs), which may be programmed in any manner known in theart. The functions of each component may also be implemented, in wholeor in part, with instructions embodied in a memory, formatted to beexecuted by one or more general or application-specific processors.

In some examples, the receiver 910 may include at least one radiofrequency (RF) receiver, such as an RF receiver operable to receive RFsignals using a licensed radio frequency spectrum band or an unlicensedradio frequency spectrum band from one or more UEs. The receiver 910 maybe used to receive various types of data and/or control signals (i.e.,transmissions) over one or more communication links of a wirelesscommunication system, such as one or more communication links of thewireless communications systems 100, 200, 300, 400, or 500 describedwith reference to FIG. 1, 2, 3, 4, or 5.

In some examples, the transmitter 920 may include at least one RFtransmitter, such as at least one RF transmitter operable to transmitsignals using a licensed radio frequency spectrum band or an unlicensedradio frequency spectrum band, in a manner similarly as discussed abovewith respect to FIG. 1, 2, 3, 4, 5, or 6. The transmitter 920 may beused to transmit various types of data and/or control signals (i.e.,transmissions) over one or more communication links of a wirelesscommunication system, such as one or more communication links of thewireless communications systems 100, 200, 300, 400, or 500 describedwith reference to FIG. 1, 2, 3, 4, or 5. In some examples, the handovermanagement component 915 may perform handover management operations anddeterminations such as discussed above with respect to FIG. 1, 2, 3, 4,5, or 6.

In the example of FIG. 9, the handover management component 915 mayinclude a measurement report reception component 925, and a handoverdetermination component 930 having an optional load determinationcomponent 935. The measurement report reception component 925, in someexamples, may receive one or more of a base station measurement reportfrom one or more different base stations of a UE measurement report fromone or more different UEs. The measurement reports may includemeasurement reports such as described with respect to FIG. 1, 2, 3, 4,5, or 6, and may include, for example, information related to one ormore transmitting devices that may be transmitting interfering signalsat a UE. The handover determination component 930, in some examples, maymake determinations related to handover of a UE to a target basestation. Such determinations may be made according to techniques such asdiscussed above with respect to FIG. 1, 2, 3, 4, 5, or 6, and may bebased on, for example, channel conditions, loading at the base station,loading at other base stations, capabilities of base stations, presenceof interfering signals at a UE, etc. The handover determinationcomponent 930 may include a load determination component 935 that mayreceive a load parameter from one or more other base stations, that maybe used in a determination of whether to handover a UE and to which basestation a UE may be handed over, such as discussed above with respect toFIG. 1, 2, 3, 4, 5, or 6.

FIG. 10 shows a block diagram 1000 of a base station 1005 (e.g., a basestation forming part or all of an eNB) for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. In some examples, the base station 1005 may be an example ofaspects of one or more of the base stations 105, 205, 305, 405, 505, or605 described with reference to FIG. 1, 2, 3, 4 5, or 6, and/or aspectsof one or more of the apparatus 1005 or 1105 when configured as a basestation, as described with reference to FIG. 10 or 11. The base station1005 may be configured to implement or facilitate at least some of thebase station and/or apparatus features and functions described withreference to one or more of FIG. 1, 2, 3, 4, 5, 6, or 9.

The base station 1005 may include a base station processor 1010, a basestation memory 1020, at least one base station transceiver (representedby base station transceiver 1050), at least one base station antenna(represented by base station antenna(s) 1055), and/or a handovermanagement component 1015. The base station 1005 may also include one ormore of a base station communications component 1030 and/or a networkcommunications component 1040. At least one of these components may bein communication with each other, directly or indirectly, over one ormore buses 1035.

The base station memory 1020 may include random access memory (RAM)and/or read-only memory (ROM). The base station memory 1020 may storecomputer-readable, computer-executable software/firmware code 1025containing instructions that are configured to, when executed, cause thebase station processor 1010 to perform various functions describedherein related to wireless communication (e.g., handover determinationoperations, etc.). Alternatively, the computer-readable,computer-executable software/firmware code 1025 may not be directlyexecutable by the base station processor 1010 but be configured to causethe base station 1005 (e.g., when compiled and executed) to performvarious of the functions described herein.

The base station processor 1010 may include an intelligent hardwaredevice, e.g., a central processing unit (CPU), a microcontroller, anASIC, etc. The base station processor 1010 may process informationreceived through the base station transceiver 1050, the base stationcommunications component 1030, and/or the network communicationscomponent 1040. The base station processor 1010 may also processinformation to be sent to the base station transceiver 1050 fortransmission through the antenna(s) 1055, to the base stationcommunications component 1030, for transmission to one or more otherbase stations 1005-n and 1005-m, and/or to the network communicationscomponent 1040 for transmission to a core network 1045, which may be anexample of one or more aspects of the core network 130 described withreference to FIG. 1. The base station processor 1010 may handle, aloneor in connection with the handover management component 1015, variousaspects of handover techniques as discussed above with respect to FIG.1, 2, 3, 4, 5, 6, or 9.

The base station transceiver 1050 may include a modem configured tomodulate packets and provide the modulated packets to the base stationantenna(s) 1055 for transmission, and to demodulate packets receivedfrom the base station antenna(s) 1055. The base station transceiver 1050may, in some examples, be implemented as one or more base stationtransmitters and one or more separate base station receivers. The basestation transceiver 1050 may support communications in a licensed radiofrequency spectrum band or an unlicensed radio frequency spectrum band.The base station transceiver 1050 may be configured to communicatebi-directionally, via the base station antenna(s) 1055, with one or moreUEs or apparatuses, such as one or more of the UEs 115, 215, 315, 415,515, 615 or 915 described with reference to FIG. 1, 2, 3, 4, 5, 6, or 9or apparatuses 705 or 805 described with reference to FIG. 7 or 8. Thebase station 1005 may, for example, include multiple base stationantenna(s) 1055 (e.g., an antenna array). The base station 1005 maycommunicate with the core network 1045 through the networkcommunications component 1040. The base station 1005 may alsocommunicate with other base stations, such as the base stations 1005-nand 1005-m, using the base station communications component 1030.

The handover management component 1015 may be configured to performand/or control some or all of the features and/or functions describedwith reference to FIG. 1, 2, 3, 4, 5, or 6 related to determination ofthe presence of interfering signals and handover of a UE. The handovermanagement component 1015, or portions of the handover managementcomponent 1015, may include a processor, and/or some or all of thefunctions of the handover management component 1015 may be performed bythe base station processor 1010 and/or in connection with the basestation processor 1010. In some examples, the handover managementcomponent 1015 may be an example of the handover management component915 described with reference to FIG. 9.

FIG. 11 shows a block diagram of a multiple input/multiple output (MIMO)communications system 1100 including a base station 1105 and a UE 1115,in accordance with various aspects of the present disclosure. The MIMOcommunications system 1100 may illustrate aspects of the wirelesscommunications systems 100, 200, 300, 400, or 500 shown in FIG. 1, 2, 3,4, or 5. The base station 1105 may be equipped with base stationantennas 1134-a through 1134-x, and the UE 1115 may be equipped with UEantennas 1152-a through 1152-n. In the MIMO communications system 1100,the base station 1105 may be able to send data over multiplecommunication links at the same time. Each communication link may becalled a “layer” and the “rank” of the communication link may indicatethe number of layers used for communication. For example, in a 2×2 MIMOcommunications system where base station 1105 transmits two “layers,”the rank of the communication link between the base station 1105 and theUE 1115 is two.

At the base station 1105, a transmit processor 1120 may receive datafrom a data source. The transmit processor 1120 may process the data.The transmit processor 1120 may also generate control symbols and/orreference symbols. A transmit (TX) MIMO processor 1130 may performspatial processing (e.g., precoding) on data symbols, control symbols,and/or reference symbols, if applicable, and may provide output symbolstreams to the base station modulators/demodulators 1132-a through1132-x. Each base station modulator/demodulator 1132 may process arespective output symbol stream (e.g., for OFDM, etc.) to obtain anoutput sample stream. Each base station modulator/demodulator 1132 mayfurther process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a DL signal. In oneexample, DL signals from base station modulator/demodulators 1132-athrough 1132-x may be transmitted via the base station antennas 1134-athrough 1134-x, respectively.

At the UE 1115, the UE antennas 1152-a through 1152-n may receive the DLsignals from the base station 1105 and may provide the received signalsto the UE demodulators/modulators 1154-a through 1154-n, respectively.Each UE demodulator/modulator 1154 may condition (e.g., filter, amplify,downconvert, and digitize) a respective received signal to obtain inputsamples. Each UE demodulator/modulator 1154 may further process theinput samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMOdetector 1156 may obtain received symbols from all the UEdemodulators/modulators 1154-a through 1154-n, perform MIMO detection onthe received symbols, if applicable, and provide detected symbols. Areceive processor 1158 may process (e.g., demodulate, deinterleave, anddecode) the detected symbols, providing decoded data for the UE 1115 toa data output, and provide decoded control information to a processor1180, or memory 1182.

The processor 1180 may in some cases execute stored instructions toinstantiate one or more of a measurement report component 1145. Themeasurement report component 1145 may be an example of aspects of themeasurement report component 715 or 825 described with reference to FIG.7 or 8.

On the uplink (UL), at the UE 1115, a transmit processor 1164 mayreceive and process data from a data source. The transmit processor 1164may also generate reference symbols for a reference signal. The symbolsfrom the transmit processor 1164 may be precoded by a transmit MIMOprocessor 1166 if applicable, further processed by the UEdemodulators/modulators 1154-a through 1154-n (e.g., for SC-FDMA, etc.),and be transmitted to the base station 1105 in accordance with thetransmission parameters received from the base station 1105. At the basestation 1105, the UL signals from the UE 1115 may be received by thebase station antennas 1134, processed by the base stationmodulators/demodulators 1132, detected by a MIMO detector 1136 ifapplicable, and further processed by a receive processor 1138. Thereceive processor 1138 may provide decoded data to a data output and tothe processor 1140 and/or memory 1142. The processor 1140 may in somecases execute stored instructions to instantiate one or more of ahandover management component 1135. The handover management component1135 may be an example of aspects of the handover management component915 or 1015 described with reference to FIG. 9 or 10.

The components of the UE 1115 may, individually or collectively, beimplemented with one or more ASICs adapted to perform some or all of theapplicable functions in hardware. At least one of the noted componentsmay be a means for performing one or more functions related to operationof the MIMO communications system 1100. Similarly, the components of thebase station 1105 may, individually or collectively, be implemented withone or more ASICs adapted to perform some or all of the applicablefunctions in hardware. At least one of the noted components may be ameans for performing one or more functions related to operation of theMIMO communications system 1100.

FIG. 12 is a flow chart illustrating an example of a method 1200 forwireless communication, in accordance with various aspects of thepresent disclosure. For clarity, the method 1200 is described below withreference to aspects of one or more of the base stations 105, 205, 305,405, 505, 605, 1005, or 1105 described with reference to FIG. 1, 2, 3,4, 5, 6, 10, or 11, and/or aspects of one or more of the apparatus 905described with reference to FIG. 9. In some examples, a base station mayexecute one or more sets of codes to control the functional elements ofthe base station to perform the functions described below. Additionallyor alternatively, the base station may perform one or more of thefunctions described below using special-purpose hardware.

At block 1205, the method 1200 may include receiving, at a first basestation, a base station measurement report comprising informationassociated with one or more first devices that transmits first signalsusing an unlicensed radio frequency spectrum band. The one or more firstdevices may include, for example, more of a non-serving base station ora non-serving WLAN AP. In some examples, one or more of the firstdevices may transmit an interfering signal that may interfere withsignal reception of a UE. In some examples, the one or more firstdevices may be within an energy detection range of a base station thatprovided the base station measurement report, and may be out of anenergy detection range of the first base station. In some examples, thebase station measurement report may include an identification and anenergy measurement of at least one of a non-serving base station or anon-serving WLAN AP. The base station measurement report also mayinclude, in some examples, preamble detection information for at leastone of the non-serving base station or the non-serving WLAN AP. The basestation measurement report may be received via a backhaul link, forexample.

The operation(s) at block 1205 may be performed using the handovermanagement component 915 or 1015 described with reference to FIG. 9 or10, measurement report reception component 925 of FIG. 9, receiver 910described with reference to FIG. 9, using the base station transceiver1050 and base station antenna(s) 1055 of FIG. 10, and/or using the basestation antennas 1134 and base station modulators/demodulators 1132 ofFIG. 11.

At block 1210, the method 1200 may include receiving, at the first basestation, a UE measurement report comprising information associated withone or more second devices that transmits second signals on theunlicensed radio frequency spectrum band. The one or more second devicesmay include, for example, one or more of a non-serving base station or anon-serving WLAN AP. In some examples, the one or more second devicesmay be within an energy detection range of the UE. The UE measurementreport may include an energy measurement associated with one or more ofthe second signals received at the UE from at least one of the one ormore second devices, in some examples. In some examples, the UEmeasurement report may include a plurality of measurements taken on aplurality of frequencies of the unlicensed radio frequency spectrum bandthat are different from a frequency of the first base station. In someexamples, the UE measurement report may include a plurality ofmeasurements taken at time intervals having a duration selected to allowthe UE to perform measurements of at a least one of a beacon signal forWLAN AP transmissions or a demodulation reference signal for other basestation transmissions.

The operation(s) at block 1210 may be performed using the handovermanagement component 915 or 1015 described with reference to FIG. 9 or10, measurement report reception component 925 of FIG. 9, receiver 910described with reference to FIG. 9, using the base station transceiver1050 and base station antenna(s) 1055 of FIG. 10, and/or using the basestation antennas 1134 and base station modulators/demodulators 1132 ofFIG. 11.

At block 1215, the method 1200 may include determining whether tohandover the UE to a second base station based at least in part on thebase station measurement report and the UE measurement report. In someexamples, the determination may be made that at least one of the one ormore devices is causing interference at the UE with signals transmittedfrom the first base station on the unlicensed radio frequency spectrumband, and that the second base station can transmit signals to the UEwith reduced interference relative to the first base station. Thedetermination may include, in some examples, that a signal strength oftransmissions of the second base station at the UE exceeds a thresholdvalue, that the second base station is within an energy detection rangeof the at least one of the one or more devices that is causinginterference at the UE, or that the second base station is within anenergy detection range of the first base station. In some examples, itmay be determined that a signal strength of the first base station atthe UE exceeds a signal strength of the second base station at the UE.In some examples, the determination of a handover may also be based atleast in part on a loading metric associated with the second basestation, which may include, for example, channel occupancy informationassociated with the second base station.

The operation(s) at block 1215 may be performed using performed usingthe handover management component 915 or 1015 described with referenceto FIG. 9 or 10, the handover determination component 930 or loaddetermination component 935 of FIG. 9, and/or the handover managementcomponent 1135 of FIG. 11, for example.

At block 1220, the method 1200 may include, in some examples,determining that at least one of the one or more devices is causinginterference at the UE with signals transmitted from the first basestation on the unlicensed radio frequency spectrum band. Thedetermination may be based on, for example, one or more UE or basestation measurement reports. The operation(s) at block 1220 may beperformed using the handover management component 915 or 1015 describedwith reference to FIG. 9 or 10, the handover determination component 930or measurement report reception component 925 of FIG. 9, and/or thehandover management component 1135 of FIG. 11, for example.

At block 1225, the method 1200 may include, in some examples,determining that the second base station can transmit signals to the UEwith reduced interference relative to the first base station. Thedetermination may be based on, for example, one or more UE or basestation measurement reports. The operation(s) at block 1225 may beperformed using the handover management component 915 or 1015 describedwith reference to FIG. 9 or 10, the handover determination component 930or measurement report reception component 925 of FIG. 9, and/or thehandover management component 1135 of FIG. 11, for example.

At block 1230, the method 1200 may include, in some examples,transmitting a handover command to the UE to initiate communicationsbetween the UE and the second base station. The handover command mayinclude instructions that the UE is to begin communications with thesecond base station, and information required to complete such ahandover. One or more communications with the second base station mayalso be initiated, to prepare the second base station for handover ofthe UE, according to some examples. The operation(s) at block 1230 maybe performed using the handover management component 915 or 1015described with reference to FIG. 9 or 10, the handover determinationcomponent 930, the transmitter 920 of FIG. 9, the handover managementcomponent 1135 of FIG. 11, the base station transceiver 1050 and basestation antenna(s) 1055 of FIG. 10, and/or using the base stationantennas 1134 and base station modulators/demodulators 1132 of FIG. 11,for example.

Thus, the method 1200 may provide for wireless communication. It shouldbe noted that the method 1200 is just one implementation and that theoperations of the method 1200 may be rearranged or otherwise modifiedsuch that other implementations are possible.

FIG. 13 is a flow chart illustrating an example of a method 1300 forwireless communication, in accordance with various aspects of thepresent disclosure. For clarity, the method 1300 is described below withreference to aspects of one or more of the UEs 115, 215, 315, 415, 515,615, 815, or 1115 described with reference to FIG. 1, 2, 3, 4, 5, 6, 8,or 11, and/or aspects of the apparatus 705 described with reference toFIG. 7. In some examples, a UE may execute one or more sets of codes tocontrol the functional elements of the UE to perform the functionsdescribed below. Additionally or alternatively, the UE may perform oneor more of the functions described below using special-purpose hardware.

At block 1305, the method 1300 may include receiving at a UE, from atleast one of a non-serving base station or a non-serving WLAN AP, asignal on an unlicensed radio frequency spectrum band. The operation(s)at block 1305 may be performed using the receiver 710 described withreference to FIGS. 7, using the UE transceiver 835 and UE antennas 840of FIG. 8, and/or using the UE antennas 1152 and UEmodulators/demodulators 1154 of FIG. 11.

At block 1310, the method 1300 may include measuring one or moreparameters associated with the signal. The measuring may include, forexample, measuring a received signal strength associated with thesignal, preamble detection on the signal, or CUBS identification on thesignal, for example. In some examples, the UE may take a plurality ofmeasurements on a plurality of frequencies of the unlicensed radiofrequency spectrum band that are different than a frequency of the firstbase station. In some examples, the UE may take a plurality ofmeasurements at time intervals having a duration selected to allow theUE to perform measurements of at a least one of a beacon signal for aWLAN AP or a demodulation reference signal for the non-serving basestation. The operation(s) at block 1310 may be performed using themeasurement report component 715 described with reference to FIG. 7,using the signal identification component 725 or signal parametermeasurement component 730 of FIG. 7, using the measurement reportcomponent 825 of FIG. 8, and/or using the measurement report component1145 of FIG. 11.

At block 1315, the method 1300 may include transmitting a UE measurementreport to a serving base station, the UE measurement report based atleast in part on the one or more measured parameters. The UE measurementreport may include, for example, one or more of preamble detectioninformation associated with the signal, information associated with asecond base station from a same deployment as the first base station, athird base station from a different deployment as the first basestation, or information associated with one or more WLAN APs that areundetectable by the first base station.

The operation(s) at block 1315 may be performed using the transmitter720 described with reference to FIG. 7, using the measurement reportcomponents 715 or 825 described with reference to FIG. 7 or 8, using themeasurement report generation component 735 of FIG. 7, using themeasurement report component 1145 of FIG. 11, using the UE transceiver835 and UE antennas 840 of FIG. 8, and/or using the UE antennas 1152 UEand UE modulators/demodulators 1154 of FIG. 11.

At block 1320, the method 1300 may include receiving, from the servingbase station, a handover command to initiate communications with atarget base station based at least in part on the UE measurement report.The operation(s) at block 1320 may be performed using the handovercomponent 830 described with reference to FIG. 8, using the receiver 710described with reference to FIG. 7, using the UE transceiver 835 and UEantennas 840 of FIG. 8, and/or using the UE antennas 1152 and UEmodulators/demodulators 1154 of FIG. 11.

At block 1325, the method 1300 may include initiating communicationswith the target base station based on the handover command. Theoperation(s) at block 1325 may be performed using the transmitter 720described with reference to FIG. 7, using the UE transceiver 835 and UEantennas 840 of FIG. 8, and/or using the UE antennas 1152 and UEmodulators/demodulators 1154 of FIG. 11.

Thus, the method 1300 may provide for wireless communication. It shouldbe noted that the method 1300 is just one implementation and that theoperations of the method 1300 may be rearranged or otherwise modifiedsuch that other implementations are possible.

In some examples, aspects from the methods 1200, and 1300 may becombined. It should be noted that the methods 1200 and 1300 are justexample implementations, and that the operations of the methods 1200 and1300 may be rearranged or otherwise modified such that otherimplementations are possible.

Techniques described herein may be used for various wirelesscommunications systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, andother systems. The terms “system” and “network” are often usedinterchangeably. A CDMA system may implement a radio technology such asCDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and Aare commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) iscommonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD),etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. ATDMA system may implement a radio technology such as Global System forMobile Communications (GSM). An OFDMA system may implement a radiotechnology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA),IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc.UTRA and E-UTRA are part of Universal Mobile Telecommunication System(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are newreleases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, andGSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies, including cellular (e.g., LTE) communicationsover an unlicensed and/or shared bandwidth. The description above,however, describes an LTE/LTE-A system for purposes of example, and LTEterminology is used in much of the description above, although thetechniques are applicable beyond LTE/LTE-A applications.

The detailed description set forth above in connection with the appendeddrawings describes examples and does not represent the only examplesthat may be implemented or that are within the scope of the claims. Theterms “example” and “exemplary,” when used in this description, mean“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other examples.” The detailed description includesspecific details for the purpose of providing an understanding of thedescribed techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand apparatuses are shown in block diagram form in order to avoidobscuring the concepts of the described examples.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), an ASIC, anFPGA or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, or any combination thereof designedto perform the functions described herein. A general-purpose processormay be a microprocessor, but in the alternative, the processor may beany conventional processor, controller, microcontroller, or statemachine. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor,multiple microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope and spirit of the disclosure and appended claims. For example,due to the nature of software, functions described above can beimplemented using software executed by a processor, hardware, firmware,hardwiring, or combinations of any of these. Features implementingfunctions may also be physically located at various positions, includingbeing distributed such that portions of functions are implemented atdifferent physical locations. As used herein, including in the claims,the term “and/or,” when used in a list of two or more items, means thatany one of the listed items can be employed by itself, or anycombination of two or more of the listed items can be employed. Forexample, if a composition is described as containing components A, B,and/or C, the composition can contain A alone; B alone; C alone; A and Bin combination; A and C in combination; B and C in combination; or A, B,and C in combination. Also, as used herein, including in the claims,“or” as used in a list of items (for example, a list of items prefacedby a phrase such as “at least one of” or “one or more of”) indicates adisjunctive list such that, for example, a list of “at least one of A,B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B andC).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can comprise RAM, ROM, EEPROM, flash memory,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the scope of thedisclosure. Thus, the disclosure is not to be limited to the examplesand designs described herein but is to be accorded the broadest scopeconsistent with the principles and novel features disclosed herein.

What is claimed is:
 1. A method of wireless communications comprising: receiving, at a first base station, a plurality of base station measurement reports, each of the plurality of base station measurement reports received from one of a plurality of base stations, the plurality of base station measurement reports including information associated with one or more first devices that transmits first signals using an unlicensed radio frequency spectrum band, and the one or more first devices different from the plurality of base stations; receiving, at the first base station, a user equipment (UE) measurement report from the UE, the UE measurement report including information associated with one or more second devices that transmits second signals using the unlicensed radio frequency spectrum band, and the one or more second devices different from the UE; determining whether to handover the UE to a second base station based at least in part on the base station measurement report and the UE measurement report; and transmitting, from the first base station, a handover command based at least in part on the determination to handover the UE to the second base station.
 2. The method of claim 1, wherein the one or more first devices or the one or more second devices are out of an energy detection range of the first base station.
 3. A method for wireless communications, comprising: receiving, at a user equipment (UE), from at least one of a non-serving base station or a non-serving wireless local area network (WLAN) access point (AP), a signal on an unlicensed radio frequency spectrum band; measuring one or more parameters associated with the signal; transmitting a UE measurement report to a first base station, the UE measurement report based at least in part on the one or more measured parameters; and receiving, from the first base station, a handover command to initiate communications with a second base station based at least in part on the UE measurement report.
 4. The method of claim 3, wherein the UE measurement report comprises information associated with a second base station from a same deployment as the first base station or a third base station from a different deployment as the first base station.
 5. The method of claim 3, wherein the UE measurement report comprises information associated with one or more WLAN APs that are undetectable by the first base station.
 6. The method of claim 3, wherein the UE measurement report comprises a plurality of measurements taken on a plurality of frequencies of the unlicensed radio frequency spectrum band that are different than a frequency of the first base station.
 7. The method of claim 3, wherein the UE measurement report comprises a plurality of measurements taken at time intervals having a duration selected to allow the UE to perform measurements of at a least one of a beacon signal for a WLAN AP or a demodulation reference signal (DRS) signal for the non-serving base station.
 8. The method of claim 3, further comprising: performing preamble detection for the signal; and wherein the UE measurement report further comprises preamble detection information associated with the signal.
 9. An apparatus for wireless communications at a first base station, comprising: a processor, memory in electronic communication with the processor; and the processor and memory configured to: receive, at the first base station, a plurality of base station measurement reports, each of the plurality of base station measurement reports received from one of a plurality of base stations, the plurality of base station measurements reports including information associated with one or more first devices that transmits first signals using an unlicensed radio frequency spectrum band, and the one or more first devices different from the plurality of base stations; receive, at the first base station, a user equipment (UE) measurement report from a UE, the UE measurement report including information associated with one or more second devices that transmits second signals on the unlicensed radio frequency spectrum band, and the one or more second devices different from the UE; determine whether to handover the UE to a second base station based at least in part on the base station measurement report and the UE measurement report; and transmit, from the first base station, a handover command based at least in part on the determination to handover the UE to the second base station.
 10. An apparatus for wireless communications at a user equipment (UE), comprising: a processor; memory in electronic communication with the processor; and the processor and memory configured to: receive, at the UE, from at least one of a non-serving base station or a non-serving wireless local area network (WLAN) access point (AP), a signal on an unlicensed radio frequency spectrum band; measure one or more parameters associated with the signal; transmit a UE measurement report to a first base station, the UE measurement report based at least in part on the one or more measured parameters; and receive, from the first base station, a handover command to initiate communications with a second base station based at least in part on the UE measurement report. 